Sound recording and reproducing machine



June 29, y1937.* 1 NEUMANN 2,085,383

SOUND RECORDING AND EPRODUCING MACHINE v Filed Feb. 25, 193.3 2 Sheets-Sheet 1 Ill/lllIl111/1/11111/111/Illull//l/(1111l;(1111111114111111/1 eraf al;

June 29, 1937. L.. NEUMANN SOUND RECORDING AND REPRODUCING MACHINE Filed Feb. 23, 1935 -2 Sheets-Sheet 2 Patented June 29, 1937 y PATENT FFICE soUND RECORDING AND RErRopuolN-a MACHINE Leopold Neumann, Vienna, Austria, assignor to Diktiermaschinen Patentverwertungs Gesellschaft m. b. H., Vienna, Austria, a company of Austria Application February 23, 1933, Serial No. ,658,226 In Austria February 29, 1932 1 Claim.

This invention relates to improvements in sound record carriers for dictation machines with mechanical sound recording and reproduction.

The objects and nature of the invention will be clearly understood from the following description taken in connection with the accompanying drawings in which Figs. 1 and 2 show a dictaphone in longitudinal section and in plan view respectively. Fig. 3 is a plan view of the correspending tape-like sound wave record carrier.

Fig. d is a cross-sectional view of sound wave record carrier on an enlarged scale.

The arrangement is operated by a' motor I on the shaft 2 of which is mounted a regulator for keeping constant the number of revolutions. A

worm t, secured to the shaft and meshing with a worm wheel 5, drives a belt pulley 6 which by means of a belt l drives a sprocket wheel 8 for feeding the recording or reproduction band 9.

The perforations, extending along each side of the band S, are engaged by the teeth or sprockets of the sprocket wheels 8 and I I. The band 9 passes from the drum I to the sprocket wheel S, makes a loop and passes to the sprocket wheel Ii,which is driven by the Wheel S by way of toothed wheels mounted on the same shaft, and from the Vwheel l i the said band passes to a drum I2, which is rotated by a belt drive. By means vof a pinion, the feed wheel Il rotates a flywheel it, thereby providing for a uniform feed of the band. A pick-up It, for recording and reproducing, bears with its needle on the band upon the wheel t. During the recording, the pick-up is connected to the lead-out of an amplifier, arranged in the apparatus. When the band has been fed for one length, the direction of rotation of the motor is reversed and the band fed in the opposite direction so that the sound waves may be re- K hollow shaft.

on said hollow shaft but they aresecured againstv corded lengthwise parallel to the sound waves rst recorded. However for this purpose, the band-drum hitherto driven must be released, and the hitherto idle drum be driven. lArrautomatic coupling comprises a hollow shaft mounted on a xed .shaft I5 and rotated by means of a belt drive 25. Two exteziorly square-section bosses it, il for the band-drum are mounted on the 'I'hese bosses are freely rotatable axial movement by pins, screwed into said bearings and engaging annular grooves in the hollow shaft. Claws on the sides of the bearings facing each other are adapted to co-operate with corresponding claws of a coupling sleeve I8 mounted on the shaft between both bearings. 'This sleeve is provided with an inclined slot, which is engaged by a pin I9 xed to the' hollow shaft. When the latter is rotating, the sleeve I8 moves in the direction of an axial component generated .by the pin I9 engaging said inclined slot. In view of this movement, the .claws at one side of the coupling sleeve engage the claws of lone of the drum bosses, thereby rotating the same. When reversing the direction of rotation of the hollow shaft, the direction of the axial ycomponent will be varied accordingly, so that the coupling sleeve engages the other drum boss and thus rotates the same in the opposite direction..

An essential feature of the present invention consists in that the band 3| is made of gelatine which may have perforations 36 therein. Up to now gelatine-bands have not been used because, when they are used for talking films, they are developed and thus treated with liquids, a treatment which they cannot stand in view of their solubility in water, While according to the present invention the band is immediately ready for reproduction ater the recording operation without any treatment whatever. Further it is known to use gelatine for plates or rollers. However it is new to use the gelatine in the form 'of a band and it has been found that this band is sufficiently strong. The use of gelatine in the shape oi a band establishes new possibilities for the automatic recording and reproduction of sounds, because only by the band-shape is the necessary capacity given and gelatine is the only material of any 'practical use. Cellon and celluloid are too hard? In the case of sound recording and reproducing machines, the use of gelatine is of advantage because it is not necessary to resort -to a hardening process between the recording operation and the reproduction operation, so that the apparatus is suitable for use in oices in View of its handiness and speed.

It is of particular advantage `to make the sound-waves carrier in the form of a foil-band. The sound-waves are applied by cutting grooves into the tape-shaped sound-waves carriers of considerable thickness. Therefore in this case the thickness of the material underneath the 4groove is smaller than the thickness of the band.

groove as it is at the smooth parts of the band.

The stylus always slides on a smooth surface on the band, so that stylus-noises are obviated, because the material is not cut but deformed. A further advantage of the use of foils is their small weight. Further.- foil-bands can be rolled far easier than' thick bands, so that they constitute an improved and inexpensive recording material 'for talking machines. Even in the case oi.' very 10 thinfoils, the strength of the same is quite sufficient.

The sound-waves groove 45 is impressed in the foil-band 44 (Fig. 4) by the stylus of the pick-up box. The band ls of the same thickness through- 15 out, even underneath the groove,` because the 20 of the material.

records are made mainly by impression. 'I'he grooves are deep and rigid and are directly pressed out in the case of ductlle material. The grooves are easily formed in view of the small resistance Metals particularly aluminium, and further non-metallicmaterials for instance i celluloid, cellon, gelatine and so forth are suited for the'band.

Under the term foils are to be understood bands of a thickness of less than 0,2 millimetre. Folls of a slightly smaller thickness than 0,1 millimetre have proven to be of particular advantage. Folls of this thickness can be readily rolled,l they are suillciently strong and possess durable and readily production in the dictation machine in the unhardened state.

LEOPOLD NEUMANN. 

